15. A good whose consumption decreases when income increases is generally called: A. a normal good. B. an inferior good. C. a substitute good. D. a complementary good.

16. A business produces 8 items and sells them for $25 each. The total cost of producing the items is $190 for explicit costs and $200 for implicit costs. Accounting profit is: A. -$190. B. $10. C. $20. D. $200.

17. Why do U.S. economists commonly refer to externalities as an example of market failure? A. firms that are required to pay social costs of externalities produce more B. externalities present a case where markets consider all social costs C. externalities present a case where markets only consider some social costs D. firms avoid having to pay social costs of externalities by lowering prices

18. If elasticity of demand is .2 and elasticity of supply is .5 and a 10% excise tax is levied on the good: A. the tax burden on suppliers will be greater. B. the tax burden on consumers will be greater. C. the tax burden will be the same for both. D. one cannot say who will bear the greater burden without knowing the tax